Compound engine.



G. J. MELLIN.

COMPOUND ENGINE.

'APPLICATION FILED DEC. 22, 1911.

` 1,025,638.A v Patented May 7, 1912.

2 SHEETS-SHEET 1.

lllllliil C. J. MBLLIN.

GOMPOUND ENGINE.'

APPLIGATION FILED M022, 1911.

Patented May 7, 1912. A

2 SHEETS-SHEET 2.

UNITED sTATEs PATENT oEEioE.

CARL J'. vlV.[,`li.I1L]N, OF SCHENECTADY, NE-W YORK, ASSIGNOR TOAMERICAN LOCOMOTI'VE COMPANY, OF NEW YORK, N. Y., A. CORPORATION 0F NEWYORK.

COMPOUND ENGINE.

To all whom t may concern Be it known that I, CARL J. MELLIN, ofSchenectady, in the county of Schenectady and State of New York, haveinvented a certain new and useful Improvement in Compound Engines, ofwhich improvement the following is a specification.

My invention relates to mechanism for enabling the operation of acompound engine to be effected, as from time to time desired, eithernormally, that is to say, by the piston of the low pressure cylinderbeing actuated by steam exhausted from the high pressure cylinder, or inthe manner of a pair of single expansion engines, c'. c., by the directadmission of boiler steam to the low pressure cylinder as well as to thehigh pressure cylinder.

My present invention is an improvement upon that for which LettersPatent of the United States No. 519,407 were granted and issued to TheRichmond Locomotive and Machine Vorks, as my assignee, under date of May8, 1894, and its object is to provide an appliance of the general typeabove specified, in which a suiiicient area shall be maintained throughthe balancing piston to insure its proper action; distortion of theguide of the intercepting valve by imperfections or variations inposition of the rough wall of the chamber of the balancing pistoneffectually prevented; ample bearing surface provided to act as a guidefor the stem of the intercepting valve; and proper balance of the valvesmaintained, without impairment by leakage past the packing rings.

The improvement claimed is hereinafter fully set forth.

In the accompanying drawings: Figure 1 is a longitudinal central sectionthrough the intercepting and emergency exhaust valve mechanism of acompound locomotive, illustrating an application of my invention, theparts being shown in the positions occupied when working live steamdirect in both cylinders of the engineLFig. 2, a similar view, with theparts shown in the positions occupied when working compound; Fig. 2a, atransverse section through the balancing piston, on the line b b of Fig.2; Fig. 3, a view, half in elevation and half in longitudinal centralsection, and on an enlarged scale, of the sleeve of the interceptingvalve stem; Fig. 4, a partial longitudinal central Specification ofLetters Patent.

Application filed December 22, 1911.

Patented May 7, 1912. serial No. 667,318.

section, on a further enlarged scale, through the intercepting valvestem; Fig. 5, a plan or top view of the balancing piston; and,

Fig. 6, a transverse section, on an enlarged scale, through the reducingvalve casing, on the line a a of Fig. 1.` i

The mechanism in which my improvement is applied is fitted and operatesin a casing, 1, which constitutes the passage way for the exhaust steamfrom the high pressure cylinder to the low pressure cylinder of acompound engine, or to the atmosphere, accordingly as the engine isworking compound or single, and which, in a locomotive engine, isordinarily a portion of one of the cylinder saddles. A receiver 2, inthe casing, 1, is in constant communication with the exhaust passage oflthe high pressure cylinder of the engine; a passage, 3, leads from thecasing to the valve chest of the low pressure cylinder; and an emergencyor direct eX- haust passage, 4, leads from the casing to an exhaustvpipe discharging into the atniosphere. A balancing chamber, 5, isinterposed between the receiver, 2, and the direct exhaust passage, 4,and a direct or live steam passage, 6, leads from the boiler to areducing valve chamber, 7, formed in a casing, 8, fixed to the maincasing, 1, said chamber, 7, communicating, through ports, 7H, with thepassage, 3, leading to the low pressure cylinder, when said ports areuncovered by a reducing valve, 9, as hereinafter described. A dash potcylinder, 10, closed by a head, 10a, having a port, 10b, leading to theatmosphere, is formed on the outer end of the casing, 8, and is .fittedwith a suitably packed piston, 11.

The discharge of exhaust steam from the receiver, 2, to the low pressurecylinder passage, 8, is controlled by an intercepting valve, 12, fixedupon one end of a valve stem, 12a, upon the opposite end of which issecured a balancing piston, 13, controlling a passage, 5a, leading fromthe receiver, 2, into the balancing chamber, 5, The balancing piston,13, is provided with circumferential ports, 13a, and small throughports, 13", theaggregate area of which is substantially less than thatof the ports, 13a, the function ofthe ports, 18h, being to maintain aconstant equilibrium of pressure between the receiver and the balancingchamber, except upon the unseating of an emergency exhaust valve, 14,which controls communication between the balancing chamber, 5, and thedirect exhaust passage, 11. -T he combined area of the circumferentialports, 13, in the balancing piston, is slightly less than the area ofthe opening controlled by the emergency exhaust valve, 14, in orderthat, as the exhaust steam passes through the ports, 13a, on its Way tothe direct exhaust passage, a constant pull Will be exerted upon thebalancing piston, tending to hold the intercepting valve closed andprevent iuttering. The emergency exhaust valve, 14, is formed integralwith, or fixed to, a piston, 15, working in a cylinder, 16, to whichsteam is admitted by a supply pipe, 16a, controlled by a valve (notshown) which is manually operated by the engineer. The piston, 15, isreturned to normal position, in which the emergency exhaust valve isclosed, by a spring, 17, bearing at one end on the cylinder, 16, and, atthe other, on a disk, 18a, fixed on a stem, 18, secured to the piston,15.

The` stem, 12a, of the intercepting valve, is made hollow or tubular,from a point adjacent to the intercepting valve to its upper or outerend, adjacent to Which the dash pot piston, 11, is secured upon it. Thereducing valve, 9, before referred to, is formed upon a sleeve, 9a,Which is fitted freely on the stem, 12a, of the intercepting valve, andcontrols communication, thro-ugh the ports, 7a, between the live steampassage, 6, and chamber, 7, and the passage, 3, leading to the lowpressure cylinder. The sleeve, 9a, is reduced in diameter, relatively tothe reducing valve, 9, and said valve and the sleeve or lesser diameterlit in corresponding differential bores in the casing, S. The sleeve,9a, is provided with packing rings, 9b, and is turned down to form alongitudinal recess, 9C, and bleed holes 9d, are formed in its Wall. Theportion of the stem, 12, of the intercepting valve which is Within thesleeve, 9a, is provided "With packing rings, 12", and it is turned downto form a longitudinal recess, 12C, Within Which bleed holes, 12d,extend from its central bore to the periphery of the recess, 12. Saidrecess pre-vents the sealing up of the bleed holes in any position ofthe sleeve, and enables leakage past the valve to escape to theatmosphere, through the central bore of the valve stem and the dash potcylinder, 10.

In the operation of the mechanism above described, when it is desired tochange the Working of the engine from compound to simple, steam isadmitted to the cylinder, 16, by the engineer, the pressure thereof onthe piston, 15, unseating the emergency exhaust valve, 14, and therebysuddenly releasing the pressure in the balancing chamber, 5, on theadjacent side of the balancing piston, 13. This reduction of pressure onsaid piston causes the receiver pressure, acting on its opposite side,to move it to the position shown in Fig. 1, thereby seating theconnected intercepting valve, 12, which operation is effected withoutbleeding the entire reservoir and thereby stalling the train, as isordinarily the case with intercepting valve mechanisms of otherconstructions. It may be here noted'that, as before explained, the smallthrough ports, 13", in the balancing piston, maintain an equilibrium ofpressure in the receiver and the balancing chamber, at allv times exceptupon the opening movement of the emergency cxhaust valve, and that, whenthe intercepting valve is seated, it is held in such position Withoutfluttering on its seat. Then working as a simple engine, the exhauststeam of the high pressure cylinder is discharged through the directexhaust passage, 4;, to an independent or emergency exhaust pipe, andlive steam is admitted to the low pressure cylinder by the reducingvalve, 9, said steam being throttled and reduced in pressure in itspassage through the ports, 7, leading to the passage.

In order to change the Working of the engine from simple to compound,steam is exhausted from the cylinder, 1G, by the engineer, whereupon thepressure acting on the top of the emergency exhaust valve, 14, inconjunction With the spring, 17, seats said valve. Equalization ofpressure then takes place in the reservoir, 2, and balancing chamber, 5,and the intercepting valve, 12, is unseated by the building up of thereservoir pressure against it. The exhaust steam of the high pressurecylinder is thereupon discharged to the lo7 pressure cylinder, throughthe passage, 3, and the supply of live steam to the low pressurecylinder is cut oif by the closure of the ports, 7a, by the reducingvalve, 9.

The practical advantages of my improvement Will be obvious to thoseskilled in the construction and operation of compound engines, in theparticulars of its embodiment of means for insuring the true rectilinealmovements of the intercepting valve to and from its seat; maintainingnormal and sufficient area for the passage of steam from the receiver tothe emergency exhaust valve; preventing undesired opening or flutteringof the intercepting valve; and maintaining proper balance of said valveWithout impairment by leakage of steam past the packing rings of thereducing valve.

I claim as my invention, and desire to secure by Letters Patent 1. In acompound engine, the combination of an intercepting valve and acylindrical balancing and guide piston, said piston being provided Witha peripheral main discharge port, and with through balancing ports oflesser area.

2. In a'compound engine, the combination of an intercepting valve, astem on which said valve is secured, an emergency exhaust valve, and abalancing piston secured on the stem of the intercepting valve andworking in a cylindrical opening in a partition interposed between theintercepting valve and the emergency exhaust valve, said piston beingprovided with a peripheral port and with through ports of lesser area. A

3. In a compound engine, the combination of an intercepting valve, astem on which said valve is secured, a sleeve mounted on said valvestem, a reducing valve fixed on said sleeve, a casing in which saidsleeve and reducing valve work, and which is provided withcircumferential ports, controlled by said valve, establishingcommunication between a live steam passage and a low pressure cylinder,and a balancing piston fitting in a balancing chamber and connected tothe intercepting valve.

4. In a compound engine, the combination of an intercepting valve, astem on which said valve is secured intermediate of its ends, said stembeing tubular throughout a portion of its length on the side of thevalve opposite the seating face thereof and open at its end to theatmosphere, a sleeve mounted on the tubular portion of said stem, areducing valve fixed on said sleeve and controlling communicationbetween a live steam passage and a passage to a low pressure cylinder,and means for discharging leakage past the reducing valve through thetubular portion `of the valve stem.

5. In a compound engine, the combination of an intercepting valve, astem on which said valve is secured intermediate of its ends, said stembeing tubular throughout a port-ion of its length on the side of thevalve opposite the seating face thereof and open at its end to theatmosphere, a sleeve mounted on the tubular portion of said stem, andhaving a circumferential recess, a reducing valve of larger diameterfixed on said sleeve, a casing in which said sleeve and reducing valvework and which is provided with ports controlled by said valve,establishing communication between a live steam passage and a lowpressure cylinder, radial ports leading through the wall of the sleeve,and similar ports leading through the tubular portion of the valve stem.

6. In a compound engine, the combination of a casing containing areceiver and having connections to a high pressure cylinder exhaustpassage, a low pressure cylinder supply passage, an emergency exhaustpassage, and a live steam passage, an intercepting valve fixed upon astem between the tubular and solid portions thereof, a dash pot cylinderto which the tubular portion of the valve stem is open, and which isitself open to the atmosphere, a balancing and guide piston fixed to thevalve stem and working in a passage between the receiver and a balancingchamber, an emergency exhaust valve controlling communication betweensaid chamber and the emergency exhaust passage, a sleeve fitting on thetubular portion vof the valve stem, a reducing valve fixed on said stem,and a casing in which said sleeve and reducing valve are iitted to workand which is provided with peripheral ports controlled by the reducingvalve and establishing communication between the live steam passage andthe low pressure cylindersu pl assage.

P y p CARL J. MELLIN. lVitnesses HAL. R. STAFFORD, A. G. Es'rns.

Copies of this patent may be obtained for ive cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

